Esters of tall oil pitch and polyoxyethylene compounds and their use as drilling fluid additives



United States Patent 3,379,708 ESTERS 0F TALL OIL PITCH AND POLYOXY- ETHYLENE COMPOUNDS AND THEIR USE AS DRlLLING FLUID ADDITIVES Dixon W. Peacock, Bartlesville, Okla, assiguor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 330,586, Dec. 16, 1963. This application Nov. 23, 1964, Ser. No. 413,316

12 Claims. (Cl. 260--97.5)

ABSTRACT OF THE DISLOSURE Esters useful as drilling mud additives are formed by heating a mixture of tall oil pitch and a polyoxyethylene compound under conditions of reflux for about 1 to 3 hours or at a temperature in the range of about 130-280" C. for about 1 to 3 hours at about atmospheric pressure.

This application is a continuation-in-part of my earlier filed application Ser. No. 330,586, field Dec. 16, 1963.

This invention relates to drilling fluids. In one aspect it relates to drilling fluids such as aqueous, oil-base, and emulsion types of drilling fluids used in drilling deep wells such as oil and gas wells. In another aspect it relates to a method for preparing and using a simple drilling fluid which exhibits low fluid loss properties and other desirable rheological properties in illitic clay drilling fluid systems. In another aspect it relates to a flocculant for bentonitic clays. In still another aspect the invention relates to a novel composition of matter which has particular utility as a drilling fluid additive.

It is well known that in perforating the earthen formations to tap subterranean deposits such as gas or oil, the perforation is accomplished by well drilling tools and a drill fluid. The drilling fluid serves to cool and lubricate the drill bit, to carry the cuttings to the surface as the drilling fluid is circulated in and out of the well, to support at least part of the weight of the drill pipe and drill bit, to provide a hydrostatic pressure head to prevent caving of the walls of the well bore, to deposit on the surface of the well bore a filter cake which acts as a thin, semiimpervious layer to prevent undue passage therethrough of fluids, and to perform other functions as are well known in the drilling art.

It is important that the drilling fluid eXhibit a relatively low rate of filtration or fluid loss in addition to having desirable rheological properties such as viscosity and gel strengths. It is also important that the drill fluid system should be kept as simple and inexpensive as possible in order to avoid undue expense in the drilling of a well.

It is therefore an object of this invention to provide an illitic clay base drilling fluid having low fluid loss characteristics. It is also an object of this invention to provide a novel composition of matter which is useful as a drilling fluid additive. Still another object of the invention is to provide a method for controlling the fluid loss properties of an illitic clay base drilling fluid without adversely affecting the rheological properties of the drilling fluid. Still another object is to provide a fiocculant for hydrophilic bentonitic clays and a dispersant for organophilic bentonitic clays. Still another object is to provide a drilling or well-working fluid which is effective in drilling fluids contaminated with salts such as sodium chloride and calcium sulfate as well as being effective in drilling fluids wherein these contaminating salts are absent. Still another object is to provide an additive for oil base drilling fluids containing organophilic bentonitic clays. The provision of a concentrate to facilitate preparation of an oil base drilling fluid in the field is yet another object of the invenwherein n is an integer of 4 to 500, R contains 0 to carbon atoms and is selected from the group consisting of hydrogen and alkyl, aryl, alkaryl, aralkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl and acyl radicals, and R is an acyl radical from an acid constituent of tall oil pitch.

Some exampes of applicable esters are those prepared by esterification of tall oil pitch with polyoxyethylene compounds of the general formula R(OCH CH OI-I, where n is 4-500, preferably 6-100, and R is hydrogen, methyl, ethyl, isopropyl, isobutyl, hexyl, octyl, dodecyl, octadecyl, triacontyl, hexacontyl, phenyl, l-naphthyl, o-tolyl, methylphenyl, m-hexylphenyl, o-octylphenyl, p-isooctylphenyl, p-nonylphenyl, o-decylphenyl, m-octadecylphenyl, benzyl, Z-phenyloctyl, cyclohexyl, 3-cyclohexylpropyl, 3- Inethylcyclopentyl, acetyl, propionyl, lauroyl, stearoyl, and the like. The nonyl'phenyl derivatives, e.g., p-nonylphenoxypoly(ethyleneoxy)ethanol, in which n has a value of 6-100, are especially good.

The additives can be utilized in water-base drilling fluids containing illitic clays to reduce the fluid loss properties of the drilling fluid Without appreciably affecting the rheological properties of the drilling fluid. Esters of tall oil pitch and polyoxyethylated nonylphenols are especially effective as fluid loss control additives in such water-base fluids and are particularly useful in low solids, illitic claycontaining water-base fluids containing salt (sodium chloride) and gypsum or anhydrite (calcium sulfate), where fluid loss control is often difficult to obtain.

The additives can also be utilized in oil-base drilling fluids containing organophilic bentonitic clays (bentones) to increase viscosity particularly when polar compounds such as sulfonated asphalt are added to the drilling fluid for fluid loss control. When about 2 to 3 pounds per barrel of the tall oil pitch ester is added to an oil-base drilling fluid containing sulfonated asphalt, the viscosity of the system is raised sufficiently to maintain weighting material such as barite in suspension without appreciably affecting the fluid loss control provided by the addition of the sulfonated asphalt.

The additives of the invention are flocculants for bentonitic clays in water-base systems and therefore are useful for rejecting bentonitic clays from drilling fluids and are useful for drilling through bentonitic clay formations with water-base drilling fluids.

Although the concentration of the additive for fluid loss control in illitic clay systems can vary over a wide range, it will usually be maintained in the range of about 4 to 20 pounds of additive per barrel of drilling fluid and the concentration will preferably be maintained between about 6 and 10 pounds of additive per barrel of drilling fluid.

The aqueous drilling fluids of this invention need contain only water and a finely-divided illitic clay; however, it is within the scope of this invention to incorporate the novel fluid loss additive into a drilling fluid containing other additives or to add other materials, except bentonitic clays, to the drilling fluid containing the novel fluid loss additive.

The addition of the composition of the invention in bentone-containing, oil-base drilling fluid systems for viscosifying such drilling fluid will usually be at least an 3 4 amount equal to that of the polar compound that was TABLE I added to control fluid loss. Often a small amount of the Add t e Reaetants composition, e.g., about 23 pounds per barrel of fluid, will Ester 1 1V 1 50 parts tall oil pitch and increase the viscosity and gel strengths of an 011 base fluid 65 parts pmonylphenoxypome thylcneoxymhanol system sufiiciently to suspend the necessary or desired 5 wherein ,1 I d 2 3parts tall oi piteian amount of weighting agent. When relatively large amounts 1 pm pnonylphenoxypomethyleneoxwethanoly of weighting agent are to be added to the system, it ma whereinfiwlm h d r 3 Zparts ta i pite an be deal-Rue to add as mud} 20 30 pounds of the 1 part; p-nonylphenoxypoly(ethyleneoxy)etha1101, composition per barrel of drilling fluid. n =1 t h d 4 4pai-tsta oi pic an In the preparation of 011 base drilling fluids containing spam pmnylphenoxypolflethyleneoxymhanol bentones it is essential that the bentones be disperse h i =g completely in the system so as to obtain maximum vis- I recoilty rap Rap 1d 18p 2 $5 5222; aim Drilling fluids of various COlIlPOSltIOl'lS were made up, qlilres a 1 5 5 93 5 u i ion afient The id and each of the ester additives in Table I was tested as mm or 01 m1 1 F f I a fluid loss control agent by the method of API Recomprfapflratlori of f F dlsgerslon {3 .2 i a mended Practice, Standard Procedure for Testing Drilling drilling fluid mixing equipment is (11 1 en 1 not impos- Fluids, API RP 13B first edition, November 1962, slble' h section 3, Filtration, Low Temperature Test, pages 8 and I have found lfhat tall 011 pltch esters of t mvan 9. In each instance the fluid loss was determined on the non can.be umlze d m preparanon of bentone'con' fresh drilling fluid after incorporation of the fluid loss tall'llng 0!1 base dnulng flu1ds and that a coflcentrataof control additive and also on additive-containing drilling bentone and oil can be prepared at a convenient location fluid which had aged f 16 hours at C. Each drilling and pp as grease-like Sohd to the dlllhng slte fluid without ester additive was used in a control test. where it can be mixed with oil utilizing normal drilling h drilling fl id compositions and test results are fluid mixing equipment to produce an oil-base drilling 25 marizedin T bl II,

TABLE II Additive, g. 2 6 10 6 6 10 10 MtCraeken Clay, g.

2 a Saturated NaCl Solu., cc. CL1SO4'7H2O, g M.V. CMGfig. Diesel Oil, cc 15 Fluid Loss, cc.Fresh Drilling Flu Base Drilling Fluid (Control)- 53.0 53.0 53.0 13.3 36.0 153.0 145.0 Drilling Fluid+A dditive 1.... 70.0 9.6 7.6 6.4 5.2 8.0 12.0 Drilling Fluid+Additive 2. 70.0 28.4 13.0 11.5 10.81G8.0 167.0 Drilling Fluid-l-Additive 3.... 110.0 13.2 7.6 8.4 12.4 23.5 28.0 Drilllng Fluid-l-Additivei 143.0 12.8 9.2 9.9 26.0 70.0 80.0 Flutirol los, cc.Drilling Fluids Aged 16 Hours Base Drilling Fluidwontrol) 47.0 47.0 47.0 12.0 30.0143.0 143.0 Drilling Fluid+Additive 1- 84.0 .4 5.0 7.2 6.0 9.8 14.6 Drilling Fluid+Additive 2. 64.0 .0 14.6 9.2 10.4 140.0 150.0 Dr lling Fluid+Additive s. .4 6.7 7.2 11.7 35.0 26.0 Drillin Fluid+Additive 4. 5 .2 8.8 9.8 33.0 67.0 72. 0

1 Weight of additive expressed in grams represents pounds of additive per barrel of drillfluid of desired viscosity. The tall oil pit-ch ester performs as a viscosifier for the bentone-containing oil base drilling fluid as well as a dispersion agent for dispersing the bentone in the oil.

Bentones are organophilic bentonite clays. The treat ment of bentonite clay to produce a bentone is well known.

Illitic clays are hydrous micas and are related to true micas but contain less potassium. The properties of illitic clays are described in Rogers, Composition and Properties of Oil Well Drilling Fluids, second edition, Gulf Publishing Company, Houston 1953 at 280282.

The following examples will be helpful in attaining an understanding of this invention; however, the specific polyoxyethylene compounds and the specific details for preparing the reaction products of the axample are merely illustrative of a preferred embodiment of the invention and are not to be construed as unduly limiting the invention.

Example I Esters for use as drilling mud additives were prepared by heating together tall oil pitch, Tallene, and a polyoxyethylated nonylphenol surfactant at about 135 C. for approximately 2% hours. Tallene contains -50% fatty acids; 24-32% resin acids; 2232% stearols, higher alcohols, etc.; a softening point between 88-108 R; an acid number between -75; and a saponification number between 90-110. The reaction product, without any separation or purification, was used as the additive. Table I shows the ratio of tall oil pitch to surfactant employed in each of 4 additive preparations.

The results in Table II show that the ester additives in concentrations greater than 2 pounds per barrel of drilling fluid served as fluid loss control agents. In general, the reduction in the quantity of fluid lost from the drilling fluids was especially great in the drilling fluids containing salt or salt and gypsum.

Example II Tall oil pitch esters were prepared by heating the reactants as described in Example I to 270 C. while bubbling CO through the mixture to remove water formed by the reaction. In this manner the reaction time could be reduced to about 1 hour. Esterification appeared to progress rapidly at about 250 C. Esters were also prepared wherein a solvent such as xylene was used to reduce the viscosity of the mixture.

Ester additive No. 5 was prepared by heating 104 parts by weight of tall oil pitch and 140 parts by weight of p-nonylphenoxypoly(ethyleneoxy) ethanol wherein 71:50 at about 270 C. for about 1 hour while bubbling CO through the mixture.

Ester additive No. 6 was prepared by refluxing 218 parts by weight of tall oil pitch; 135 parts by weight of p-nonylphenoxypoly (ethyleneoxy) ethanol wherein n=30; 40 parts by weight of glycerine; and 215 parts by Weight of xylene, for 1 hour, removing moisture by means of a moisture trap. The product contained 58 weight percent of the ester.

Example III Ester additives 5 and 6 were added to aqueous drilling fluids containing an illitic clay marketed as P- clay and the treated drilling fluids were tested as in Example I. The results are shown in Table III:

TABLE III.-FLUID LOSS IN 25 LBJBBL. P95 DRILLING FLUID [30 minute water loss, aged 16 hours at 80 (3.]

Treatment, lb./bbl 3 5 Ester #5 28 5. 2 3. 2 1. 8 Ester #6 28 16. 6 9. 2 4. 4 Ester #6 1 28 9. 3 5. 3 2. 6

1 Solvent-tree basis, assuming no eflect for the solvent.

The above results demonstrate the water loss control achieved with the esters prepared at the higher temperaturc.

Example IV An aqueous drilling fluid containing weight percent kaolin and 4 weight percent bentonite was treated with ester #1. The properties of the drilling fluid and the results of the treatment are shown in the following Table IV.

TABLE IV.FLOCCULATION OF BENTONITE Treatment, lb./bb1 Plastic Viscosity, cp

0 3. 23 Too thick to stir.

Diesel oil 1200 Bentone 121 Sulfonated asphalt 50 Acetone 24 The mixture was milled to viscouse liquid state. The mill will not handle a grease. The addition of 60 to 100 parts by weight of an ester of the invention with milling produces a concentrate having the consistency of a grease.

A drilling fluid was prepared according to the recipe of Table VI.

TABLE VI.DRILLING FLUID #1 Parts by weight Diesel oil 200 Formulation #1 150 Ester #6 20 TABLE VII.DRILLING FLUID #2 Parts by weight Diesel oil 332 Bentone 13.1 Sulfonated asphalt 5.5 Ester #6 20 Drilling fluid #2 was mixed for 30 minutes and tested. Then 200 parts by weight of barite was added and after mixing for 30 minutes the fluid was tested again. Results are shown in Table VIII.

TABLE VIIL-COMPARISON OF PREDISPERSED BENTONE- ]%%%IIEII:IISING FLUID WITH CONVENTIONAL BENTONE- Ops. Lbs/ ft.

Drilling Fluid Apparent Iflastic Yield Initial 10 Minute Viscosity Viscosity Point Gel Gal #1 13 8 9 7 11 #1+Barite 21 14 13 9 13 #2 9 5 7 6 6 #2+Barite 21 17 7 5 7 The 30-minute fluid loss from #1 weighted with barite was 6.4 cc. whereas the fluid loss from #2 weighted with barite was 11.4 cc.

The results above show that a drilling fluid prepared from the concentrate is superior to a drilling fluid prepared from the various components at the well site in the properties of viscosity, gel strength and fluid loss.

Example VI A diesel oil-bentone mixture containing about 2 weight percent bentone was used in the preparation of drilling fluids for suspending barite Weighting material.

TABLE IX Parts by weight Oil-bentone mixture 450 Sulfonated asphalt 15 Barite 200 The above drilling fluid will not suspend barite.

TABLE X Parts by weight Oil-bentone mixture 430 Sulfonated asphalt 15 Tall oil pitch ester #6 20 Barite 200 The above drilling fluid suspended barite satisfactorily. The 30 minute fluid (oil) loss was 12 cc.

TABLE x1 Parts by weight Oil-bentone mixture 430 Sulfonated asphalt 15 Tall oil pitch ester #6 20 Zinc stearate 5 Barite 200 The above drilling fluid suspended barite satisfactorily. The 30 minute fluid loss was 10.7 cc. The zinc stearate reduced fluid loss. The addition of 5 parts by weight of California (Coalinga) asbestos to the above drilling fluid increased the 30 minute fluid loss to 12.4 cc.

1 Ester additive #7 was prepared by heating equal parts by weight of tall oil pitch and p-nonylphenoxypoly(ethyleneoxy) ethanol wherein 11:50 in xylene. The product contained 59 Weight percent ester.

The above drilling fluid suspended barite satisfactorily and had a 30 minute fluid loss of 34.5 cc.

I have found that 2 parts by weight of tall oil pitch should be reacted with from 1 to 6 or more parts by weight of polyoxyethylene compound for best results in water loss control; however, beneficial results are obtained when the reactants are utilized in proportions outside this range. The reaction conditions of the example are satisfactory but these conditions are not critical and simple routine experimentation will determnie the optimum conditions for each ester.

I have found that esters prepared from tall oil and polyoxyethylene compounds do not provide any appreciable amount of water loss control, particularly in drilling fluids containing substantial amounts of salt or gypsum.

The esters of the invention do not change appreciably the viscosity and gel strength of the drilling fluid.

That which is claimed is:

1. A composition of matter consisting essentially of the reaction product obtained by heating to a temperature in the range of about 130 to about 280 C. for about 1 to 3 hours at atmospheric pressure a mixture of tall oil pitch and a polyoxyethylene compound having the formula R(OCH CH ),,OH wherein n is an integer of 4 to 500, R contains to 60 carbon atoms and is selected from the group consisting of hydrogen and alkyl, aryl, alkaryl, aralkyl, cycloalkyl, cycloalky-lalkyl, 'alkylcycloalkyl, and acyl radicals.

2. The reaction product of claim 1 wherein the polyoxyethylene compound is a mono-ether of a polyethylene glycol, n is 6 to 100, and R is alkaryl containing 7-60 carbon atoms.

3. The reaction product of claim 1 wherein the polyoxyethylene compound is a mono-ether of a polyethylene glycol, n is 9 to 50, and R is nonylphenyl.

4. The reaction product of claim 3 wherein R is p-nonylphenyl.

5. The reaction product of claim 3 wherein R is m-nonylphenyl.

6. The reaction product of claim 3 wherein R is o-nonylphenyl.

7. A process for preparing a composition of matter consisting essentially of the reaction product of tall oil pitch and a polyoxyethylene compound having the formula R(OCH CH OI-I wherein n is an integer of 4 to 500, R contains 0 to 60 carbon atoms and is selected from the group consisting of hydrogen and alkyl, aryl, alk-aryl, aralkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, and acyl radicals which process comprises heating a mixture of tall oil pitch and polyoxyethylene compound to a temperature in the range of about 130 to about 280 C. for about 1 to 3 hours at about atmospheric pressure.

8. The process of claim 7 wherein CO is bubbled through the reaction mixture to aid in the removal of water formed by the reaction.

9. The process of claim 7 wherein a mixture of tall oil pitch and polyoxyethylene compound is diluted with about an equal amount of xylene and heated at the reflux temperature of the xylene for about 1 to 3 hours under conditions of reflux with water being removed as formed.

10. The process of claim 9 wherein the xylene is paraxylene.

11. The process of claim 9 wherein the xylene is metaxylene.

12. The process of claim 9 wherein the xylene is orthoxylene.

References Cited OTHER REFERENCES Tall Oil and Its Uses, published by F. W. Dodge Co., a division of McGraw-Hill, Inc., 1965, page 16 relied u on.

Zimmerman et al.: Handbook of Material Trade Name, page 555 (1953), copy available in scientific library, call N0. TP151.25.

Richters Organic Chemistry, Translation by P. E. Spielman, volume 1 of the Aliphatic Series, published by P. Blakistons S011 and Company, Philadelphia (1915), page 317 relied upon.

DONALD E. CZAJA, Primary Examiner.

F. MCKELVEY, Assistant Examiner. 

